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Shedd Aquarium Studies Invasive Fish Species Impacting the Great Lakes Ecosystem

Contributing Editor Dr. Jordan Schaul interviews Shedd Aquarium researchers about the facility’s Great Lakes conservation research programs, which include studies on invasive species.

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In the face of all the threats that challenge the Earth’s pelagic and coastal zones of fresh water, marine and brackish water bodies, Shedd Aquarium remains committed to the conservation of aquatic life wherever it exists. While some studies have required the deployment of staff and associates to far off places, others necessitate working in Shedd’s own backyard.

The Aquarium has deployed biologists to the coastal waters of Southeast Asia to study seahorses and to Bristol Bay, Alaska to conserve beluga whales, among other distant field sites. Shedd’s biologists are also working out of the Chicago-based aquarium. Shedd Aquarium’s president and CEO, Ted Beattie is very practical about conservation and has said that “conservation starts right here, in our own backyard.” Since Shedd’s campus literally sits right on the shore of Lake Michigan, the Aquarium has focused several initiatives on protecting the Great Lakes ecosystem.

The five Laurentian Great Lakes hold the largest supply of freshwater on Earth and unfortunately, the Great Lakes are in great trouble. The National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory cites several threats to Great Lakes basin and ecosystems. Threats directly affecting surface water and aquatic life in the lakes include small scale disturbances such as weather-induced erosion, water level changes associated with climate change, pollution, and invasive species of plants, micro-organisms and animals.

The Aquarium is most poised to address invasive species concerns, and they are also interested in contributing to the conservation of native species through other research and conservation measures. The eradication of invasive species and the protection of native species is the ultimate goal, but first the Aquarium and their partners must learn more about the basic biology of these exotic and native fisheries.

More than 180 non-native species have been introduced to the Great Lakes ecosystem since the early 1800′s, from parasitic lampreys to the destructive zebra and quagga mussels. Among fish species that have found their way into these lakes, which comprise 21% of the Earth’s surface freshwater, 25 species have become established in the lakes.

In this first in a series post of posts discussing the Great Lakes Program at the Shedd Aquarium, I interview Senior Research Biologist Dr. Philip Willink. Dr. Willink is coordinating the invasive and migratory fish species studies.

Interview:

Jordan: In an effort to mitigate the detrimental impact of invasive fish species on the freshwater ecosystem, the Shedd has embarked on efforts to study the basic biology of the two invaders. The first is the weatherfish (Misgurnus anguillicaudatus), a popular cold water aquarium fish, which is suspected to have been introduced into Chicago waterways by well-intentioned hobbyists. The second is the highly aggressive round goby (Neogobius melanostomus), which following its introduction via the ballast water of cargo ships, became a popular prey item for the once threatened Lake Erie water snake. Can you elaborate on how these species became established in the Great Lakes and what you have learned about them thus far?

Philip: Weatherfish are originally from Southeast Asia, but have been moved around the world by the pet trade and through restaurants; they are a popular and hardy pet, and even a food source in some places. They first appeared on the north side of Chicago in the late 1980s, but remained largely unnoticed because they live along the bottom and will even burrow into mud to hide. Unbeknownst to people at the time, the weatherfish spread throughout the Chicago River and beyond. We aren’t sure what makes them able to thrive in the region, which is one reason whymore studies are needed.

We now find weatherfish in wetlands throughout the Chicago region. Because of their stealthy nature, their exact distribution and impact on native species is still unknown. To address this, we are studying what they eat, where they live, spawning behavior, and how they disperse into new areas.

Many invasive species arrive in the Great Lakes by attaching to gear or vehicles transported between bodies of water. The round goby was an unintentional hitchhiker that found a ride in the ballast tanks of freighters traveling from the Black Sea to the Great Lakes. They rapidly spread throughout the Great Lakes and their competition has devastated small benthic fishes. They are also unpopular with perch anglers because of their propensity for stealing bait.

However, there are drawbacks and benefits to the presence of round gobies in our lakes. As you mentioned, the comeback of the threatened Lake Erie water snake is largely attributable to their taste for round gobies, which make up most of their diet. Also, bass love to eat gobies, and bass numbers have exploded in parts of the Great Lakes, much to the delight of anglers. While round
gobies eat zebra mussels, another dangerous invasive species, they don’t eat enough to control the mussel population. These tradoffs highlight the complexity of invasions, and how much we still have to learn about the biology of these species.

Jordan: According to Shedd’s Great Lakes Program, the Aquarium’s science initiatives “develop and leverage crucial research partnerships with universities, agencies and other NGO’s.” Their research programs are designed to advance the understanding of aquatic wildlife and habitats of the Great Lakes and associated local water ways in order to develop “effective management strategies” for the region. Can you talk about some of the partnerships with regard to the coordination of these studies? What institutions are responsible for the different aspects of the invasive species research program?

Philip: The Great Lakes basin has a strong research community that is dedicated to stopping the introduction of invasive species and trying to eradicate, or at least mitigate the impacts of those that are already established. No one institution has the resources to do this alone, so institutions have to work together.

At Shedd, collaboration is key to the success of our programs. A single invasive species project around Lake Michigan may involve the U.S. Army Corps of Engineers for navigable waterways, the Illinois Department of Natural Resources for field surveys, Forest Preserve Districts and nongovernmental organizations for land access, and regional universities, such as Loyola University and Western Illinois University, that help conduct genetic analyses of specimens. Our combined expertise leads to the development of effective management strategies for Great Lakes wildlife and habitats—and of course, Shedd is always looking to partner with organizations that want to make a difference for the lakes.

Jordan: Can you summarize some of the project goals for the invasive species research. Are there fundamental differences in the ecology or behavior of the round goby and weatherfish that dictate the ways in which you will go about studying the two species?

Philip: The project goals are to gain a better understanding of their foraging, reproduction, and dispersal behaviors so we can create management plans that limit their impact on native ecosystems. “Limiting their impact” can mean eliminating them from a given area or preventing their spread to another place.

The most striking difference is their habitat preference: weatherfish live in wetlands, whereas round gobies live in streams or along rocky lake shores. This means each invasive species is interacting with a different cast of native species in a different ecological context. We are unable to automatically take what we learn from one invasive species and apply it to the other, except in a very general manner.

Each invasive species has its own unique suite of characteristics, so it’s critical for us to study them individually to increase the scientific community’s knowledge of their biology. For example, round gobies spread through streams, but the presence of a tall dam effectively halts their spread. On the other hand, weatherfish live in wetlands: technically, roadside ditches are wetlands. So weatherfish can use roadside ditches to move from watershed to watershed. The strategies we develop to control these two invasive species will be very different.

Jordan: A number of anthropogenic factors have lead to the decline of native fish species of the Great Lakes. Some of these factors have lead to the extirpation of migratory species like the Atlantic salmon. Can you talk about the migratory fish studies you are conducting at the Shedd?

Philip: The Great Lakes are rich in fish biodiversity, but we have a lot to learn. Basic biological and behavioral information about migratory fishes remains unknown, which makes it challenging to develop species management recommendations or to understand how activity on land could impact migration in the water. Shedd has a unique opportunity to study a fish migration that appears to be on the rebound.

The largest commercial fishery in the Great Lakes is the lake whitefish, Coregonus clupeaformis. Historically, lake whitefish spawned in the Great Lakes themselves, as well as some of the rivers flowing into the Great Lakes. But they were hard hit by overfishing, sea lamprey, dams, and logging that destroyed spawning grounds. Migratory spawning runs in rivers disappeared. Tighter regulations on the fishing industry, sea lamprey control efforts, and habitat restoration have resulted in an increase in whitefish numbers. Recently, biologists have noticed that whitefish are once again trying to migrate up rivers, attempting to reclaim territory that was once theirs.

We are studying why this behavior has re-emerged and how we can encourage it in order to stimulate this valuable native commercial fishery.  This work is another example of how partnerships can strengthen research: Shedd is working with the Center for Limnology at the University of Wisconsin-Madison, the Wisconsin Department of Natural Resources, the Michigan Department of Natural Resources, the U.S. Geological Survey-Great Lakes Science Center, and the University of Michigan Museum of Zoology. What we learn from this project will hopefully be applied to the spawning behaviors of other native species, like lake trout.